Dr. Alois Stankiewicz Gmbh

Manfred Hoffmann

Heinemann Gahlau

Christoph Kittel

Klaus Wittenmayer

Ehrenfried Blumel

Thomas Stankiewicz

Norbert Seemann

Gerhard Burak

Hans Walendy

Johann Tonhauser

Dieter Karg

A sound insulating structure is provided which is made by foam-backing a carpet in a single operation and which includes a consolidated layer with few or no cells followed by a cellular soft elastic layer. To this end structured materials such as fleece and/or cut foam into which foaming takes place in order to form the consolidated layer, are provided on the back of the carpet or of a foam-proof covering thereon.

Process for manufacturing a sound insulating structure

Viscoelastic plastics materials having a dynamic elasticity modulus of 10.sup.7 to 10.sup.10 Nm.sup.-2 and a loss factor of at least 5 are used for the manufacture of motor vehicle parts, such as wheel housing parts, instrument panels, and door panels, in order to reduce interior noise.

Interior noise reduction in motor vehicles

The invention relates to an adhesive insulating system (3) that is non-destructively removable, e.g. for repair purposes, for sound insulation of partition walls (1), particularly in motor vehicles. Between the foundation and the overlying layers of the insulating system (3) a layer (2) of a highly under-cross-linked polyurethane material or a special bitumen mixture is applied that has a strong adhesive effect and thus enables a force-locked connection to be made between the foundation (1) and the insulating system (3). To ensure that the desired flexibility is obtained together with unchanged acoustic effectiveness even when a carpet (8) is laid on the insulating system (3) or its heavy layer (6), according to the invention a decoupler (7) of soft elastic, predominantly open-pored material is arranged between the carpet (8) and the heavy layer (6). Surprisingly, along with the desired flexibility, the acoustic effect is further improved.

Adhesive insulation system

A three-dimensional, formable constructional element (1) with acoustic properties is provided, having a shell (2) with a low natural bending stiffness to which webs (3) are fixed so as to form a cellular grid. It is important that over the whole extent of the shell (2) the dimensions both of the webs (3) and of the cells (4) that they form together with the shell (2), and also the shape of the shell (2) itself, can be freely chosen. The cells (4) are closed on the outside on the side distant from the shell (2) by a foil system (5) that includes flattened, in particular lens-shaped, air pockets (6). In this way optimum acoustic tuning can be achieved in respect of the incident sound waves on the air-filled cell chambers utilizing frictional damping, so as to achieve maximum absorption of airborne sound.

Constructional element with acoustic properties

The invention relates to an adhesive insulating system that is non-destructively removable, e.g. for the purpose of repair, for sound insulation of partition walls, particularly in motor vehicles. To overcome the disadvantages associated with the previous systems in mounting and also in repair a layer of material of a highly under-cross-linked polyurethane is now applied between the substrate and the overlying layers. This polyurethane layer has, owing to its under-cross-linking, a great adhesive effect and thus enables the substrate and the insulating layers to be joined in a force-locked manner. The adhesive material layer can be prefabricated or is prepared by spraying on a highly under-cross-linked 2-component mixture of the polyurethane former.

A sound insulation part for surfaces with known source-sink distribution, in particular in passenger spaces of motor vehicles, is provided, which is designed as a mass-spring system with discontinuities incorporated therein for the purpose of converting sources into sinks. In order to achieve a particularly effective sound insulation with low mass or light weight, the sound insulation part contains, over limited parts of its surface, closed cells (1) embedded in the spring (foam 3) and encased in coils (2). These cells (1) can be directed towards the heavy layer (4) or the panel (8) which the part adjoins, or can be wholly or partly in the intermediate region. The cells (1) can be gas- or air-filled. The foils (2) advantageously have masses of about 25 to 150 g/m.sup.2 of surface.

Sound insulation part for surfaces

In order to subject sound-emitting surfaces of motor vehicles to localized interference with the sound field, for example, sound obstruction and attenuation, it is already known to insulate the region of the sound sources against noise by cladding the passenger space from within at the relevant point of the wall to be insulated by application of a heavy layer and of a resilient layer which, if necessary, is impregnated with a sound-attenuating material. However, limits are imposed on a sound-insulating cladding of this kind even when further sound-reducing materials are applied, as the transmission of sound energy to the interior space of the motor vehicle then takes place in other ways. In order to remedy this, at least one sound sink is subjected to intensified sound absorption by providing on the wall (2,3) a sound-insulating cladding (6/7). Specifically this cladding comprises a resilient layer (6) preferably made of foam material or fleece which is covered by a heavy layer (7).

Growing community of inventors

Nienhof, Germany

Manfred Hoffmann